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| United States Patent |
6,264,734
|
|
Dickens
|
July 24, 2001
|
Method for forming insulated products and building products formed in
accordance therewith
Abstract
A method for forming building products from heat insulated material and
building products formed in accordance therewith includes providing a mold
configured with inner dimensions equal to the desired configuration of the
building material block; providing a fluid mixture of heat insulating
material formed from a predetermined composition of ingredients; providing
at least one rigid reinforcement member and placing the reinforcement
member in the mold; introducing the fluid mixture into the mold with the
at least one reinforcement member and allowing the fluid mixture to harden
within the mold and removing the mixture from the mold resulting in a
block of reinforced heat insulating building material. The present
invention is also directed to a block of reinforced heat insulated
building material according to the method.
| Inventors:
|
Dickens; Luther (Radford, VA)
|
| Assignee:
|
RADVA Corporation (Radford, VA)
|
| Appl. No.:
|
012948 |
| Filed:
|
January 23, 1998 |
| Current U.S. Class: |
106/600; 52/600; 52/602; 52/603 |
| Intern'l Class: |
C04B 014/04 |
| Field of Search: |
106/600,632
252/62
52/503,504,505,506.01,600,602,603,606,609,611,722.1,737.6,444
264/333
|
References Cited
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| 1657861 | Jan., 1928 | Lucas.
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| 1842828 | Jan., 1932 | Giuliani.
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| 2438528 | Mar., 1948 | Wilhelm et al.
| |
| 3012525 | Dec., 1961 | Thomas.
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| 3496691 | Feb., 1970 | Seaburg et al.
| |
| 3669299 | Jun., 1972 | Jones et al.
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| 4001126 | Jan., 1977 | Marion et al.
| |
| 4069283 | Jan., 1978 | Rauchfuss | 264/32.
|
| 4110499 | Aug., 1978 | Harrison.
| |
| 4171985 | Oct., 1979 | Motoki et al.
| |
| 4446040 | May., 1984 | Samanta | 252/62.
|
| 4462835 | Jul., 1984 | Car.
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| 4533393 | Aug., 1985 | Neuschaeffer et al.
| |
| 4668548 | May., 1987 | Lankard | 428/63.
|
| 4680059 | Jul., 1987 | Cook et al. | 252/62.
|
| 4946811 | Aug., 1990 | Tuovinen.
| |
| 4984401 | Jan., 1991 | Baldino | 52/378.
|
| 4985163 | Jan., 1991 | Kratel et al. | 252/62.
|
| 5015606 | May., 1991 | Lang et al.
| |
| 5035100 | Jul., 1991 | Sachs | 52/741.
|
| 5048250 | Sep., 1991 | Elias | 52/437.
|
| 5066440 | Nov., 1991 | Kennedy et al. | 264/69.
|
| 5312806 | May., 1994 | Mogensen.
| |
| 5482904 | Jan., 1996 | Kawabe et al. | 252/62.
|
| 5520729 | May., 1996 | Engert et al. | 106/601.
|
| 5556689 | Sep., 1996 | Kratel et al. | 428/137.
|
| 5566521 | Oct., 1996 | Andrews et al. | 52/606.
|
| 5705106 | Jan., 1998 | Kolesnikov et al. | 264/29.
|
| 5749960 | May., 1998 | Belyayev | 106/600.
|
| 5934037 | Aug., 1999 | Bundra | 52/603.
|
| Foreign Patent Documents |
| 2060239 | May., 1996 | RU.
| |
Primary Examiner: Marcantoni; Paul
Attorney, Agent or Firm: McGuireWoods LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation-in-part of Ser. No. 08/821,094
filed on Mar. 20, 1997, FORMULATION FOR PRODUCING HEAT INSULATING MATERIAL
AND METHOD FOR PRODUCING THE SAME, which issued as U.S. Pat. No. 5,749,960
on May 12, 1998.
Claims
I claim:
1. A heat insulated, reinforced block of building material comprising:
a molded body defining a volume and being formed from a hardened fluid
mixture of heat insulating material, said fluid mixture of heat insulating
material being formed from a composition of ingredients;
at least one reinforcement member disposed in the volume of the body, the
reinforcement member being an elongate channel including a center portion
having sides and two side portions, each of the side portions connected to
the respective sides of the center portion, said elongate channel being
filled by said hardened fluid mixture of heat insulating material;
wherein at least a portion of each of the reinforcement members is enclosed
by the molded body.
2. A heat insulated, reinforced block of building material according to
claim 1 wherein said fluid mixture of heat insulating material is formed
from a composition of the following ingredients, in the following amounts:
a.) water glass 32-52% by weight
b.) sodium hydroxide 3-4% by weight
c.) filler 25-36% by weight
d.) iron silicon 20-22% by weight.
3. A heat insulated, reinforced block of building material according to
claim 1 and further comprising a plurality of hardened structures of heat
insulating material formed from the same composition of ingredients as the
molded body, each of the plurality of hardened structures disposed
internally within said volume of the molded body, at least one of said at
least one reinforcement member disposed between at least two of said
hardened structures.
4. A heat insulated, reinforced block of building material according to
claim 3 wherein said hardened structures of heat insulating material are
formed from a composition of the following ingredients, in the following
amounts:
a.) water glass 32-52% by weight
b.) sodium hydroxide 3-4% by weight
c.) filler 25-36% by weight
d.) iron silicon 20-22% by weight.
5. A heat insulated, reinforced block of building material according to
claim 1 wherein said at least one reinforcement member is formed from
steel.
6. A heat insulated, reinforced block of building material according to
claim 1 wherein at least one of said at least one reinforcement member is
entirely enclosed within said molded body and extends widthwise of the
molded body.
7. A heat insulated, reinforced block of building material according to
claim 1 including a plurality of reinforcement members, each of the
reinforcement members extending longitudinally along said block and at
least a portion of at least one reinforcement member forming at least a
portio an outer wall of said block.
8. A heat insulated, reinforced block of building material according to
claim 1 wherein said heat insulating material is formed through an
exothermic reaction that produces a formulation that hardens without the
use of an external energy source.
9. A heat insulated, reinforced block of building material according to
claim 2 wherein said filler is formed of firing clay.
10. A heat insulated, reinforced block of building material according to
claim 2, wherein said water glass has a SiO.sub.2 /Na.sub.2 O ratio
(modulus) that is within the approximate range 2.4 to 3.0 with a density
of approximately 1.41 to 1.47 gm/cm.sup.3.
11. A heat insulated, reinforced block of building material according to
claim 2 wherein said water glass is sodium silicate.
12. A heat insulated, reinforced block of building material according to
claim 1 wherein said fluid mixture of heat insulating material is formed
from a composition of water glass, sodium hydroxide, filler, and iron
silicon.
13. A heat insulated, reinforced block of building material according to
claim 3 wherein said at least one reinforcement member disposed between at
least two of said hardened structures is in physical contact with at least
one of the hardened structures.
14. A heat insulated, reinforced block of building material according to
claim 13 wherein said at least one reinforcement member disposed between
at least two of said hardened structures is in physical contact with two
of the hardened structures.
15. A heat insulated, reinforced block of building material according to
claim 13 wherein said at least one reinforcement member disposed between
at least two of said hardened structures is entirely enclosed within said
molded body.
16. A heat insulated, reinforced block of building material according to
claim 7 wherein the at least a portion of the at least one reinforcement
member forming at least a portion of an outer wall of said block includes
the center portion of the respective reinforcement member.
17. A heat insulated, reinforced block of building material according to
claim 16 wherein the at least a portion of the at least one reinforcement
member forming at least a portion of an outer wall of said block includes
one side portion of the respective reinforcement member.
18. A heat insulated, reinforced block of building material according to
claim 17 wherein the side portion of each respective reinforcement member
not forming an outer wall of said block is substantially enclosed by the
molded body.
19. A heat insulated, reinforced block of building material according to
claim 3, wherein at least one of the plurality of hardened structures is
in the shape of a cube.
20. A heat insulated, reinforced block of building material according to
claim 3, wherein at least one of the plurality of hardened structures is
in the shape of a cylinder.
21. A heat insulated, reinforced block of building material comprising:
a molded body defining a volume and being formed from a hardened fluid
mixture of heat insulating material, said fluid mixture of heat insulating
material being formed from a composition of the following ingredients in
approximately these proportions:
a.) water glass 32-52%,
b.) sodium hydroxide 3-4%,
c.) filler 25-36%,
d.) iron silicon 20-22%;
at least one reinforcement member disposed in the volume of the body, the
reinforcement member being an elongate channel including a center portion
having sides and two side portions, each of the side portions connected to
the respective sides of the center portion, said elongate channel being
filled by said hardened fluid mixture of heat insulating material;
wherein at least a portion of each of the reinforcement members is enclosed
by the molded body.
22. A heat insulated, reinforced block of building material according to
claim 21 wherein said filler ingredient is a firing clay.
23. A heat insulated, reinforced block of building material according to
claim 21 wherein said water glass ingredient has a SiO.sub.2 /Na.sub.2 O
(modulus) that is within the approximate range 2.4 to 3.0 with a density
of approximately 1.41 to 1.47 gm/cm.sup.3.
24. A heat insulated, reinforced block of building material according to
claim 21 wherein said at least one reinforcing member is positioned
wherein at least a portion of said reinforcement member forms at least a
portion of an outer surface of said block of building material and extends
longitudinally along said block.
Description
BACKGROUND OF THE INVENTION
The present application relates broadly to heat insulating materials and,
more precisely, to building products, especially those produced according
to a formulation that produces a heat insulating material that can
withstand a broad range of temperatures and which is formed through an
exothermic reaction that is initiated at normal room temperature
conditions or at lower, even cold, temperatures without requiring a
heating source.
There are certain known means for producing heat insulating materials for a
variety of purposes or equipment, each usually requiring some external
heat source. The resulting heat insulating material is therefore not
formed during normal room environmental conditions, which can make the
production of heat insulating material in large-dimensional constructed
forms difficult and expensive due to energy and control requirements.
Additionally, the currently known heat insulating materials often do not
have a resistance to heat that exceeds 900.degree. C., which consequently
narrows the potential range of their application. In addition, it may
become desirable to form building materials at a construction site or "in
the field." This is a virtual impossibility with materials requiring an
external heat source.
For another example, U.S. Pat. No. 4,110,499 discloses a heat protective
material that requires the material to be subjected to temperatures in the
range of 2000.degree. F. to 2500.degree. F. in order to obtain maximum
strength. U.S. Pat. No. 5,015,606 discloses a lightweight ceramic material
for building purposes that is produced by firing a foamed mixture at
temperatures above 600.degree. C. Further, U.S. Pat. No. 5,312,806
discloses mineral fibers that are for use in thermal insulation, which is
made through a process that requires a coke-heated cupola furnace that
operates at temperatures in the range of 1565.degree. C. to 1605.degree.
C. When the production of heat insulating material requires the use of an
external heat source, the process for such production leads to a
significant increase in the heat insulating material's costs.
Moreover, there are currently known heat insulating materials that use iron
silicon and which may need to have heat firing during the production of
the heat insulation materials. For example, a known method for making
highly porous items for heat insulating equipment, consists of the use of
a mixture into which a finely milled metallic silicon or iron silicon is
introduced with a finely dispersed material, such as diatomite, trepel or
marshalite. A liquid glass, or, as is known, a water glass, is then added
in the amount necessary for turning the mixture into a thick creamy
consistency. The mixture is then thoroughly mixed and heated, causing the
iron silicon or silicon to react in the alkaline medium of liquid glass.
For another example, U.S. Pat. No. 4,171,985 discloses the use of iron
silicon with water glass in the temperature range from 5.degree. to
90.degree. C. in which the unaided reaction may take 24 hours to come to
completion, so that heating to 90.degree. C. is suggested "as a matter of
course." The problem with this above-described process is that the
chemical reaction which produces the heat insulating material either does
not start at all without heating or requires a long time to come to
completion without heating. Additionally, when heat is required for the
chemical reaction, the hardening of the mixture occurs during
post-reaction cooling. This limits the applicability of such a mixture or
process in large-dimensioned constructed forms because of associated
dimensional changes. Further, the process described in the 985 Patent
requires the use of the water-soluble alkali silicate, alumina cement, a
metal base foaming agent and a foam stabilizing agent to produce its heat
insulating material. The use of these four elements limit the
applicability of the heat insulating material production during field
conditions and in construction forms of large dimensions that do not have
an external heat source.
In order to overcome the above-mentioned defects in the previously
mentioned heat insulating building materials, there is a need for specific
building materials formed from a formulation for heat insulating material
and a method for making the same that includes a self-starting chemical
reaction that leads to a dimensionally stable, structurally strong product
and which initiates at normal room or lower temperatures which eliminates
the need for external heating or firing. Further, there is a need for
building materials formed from a heat insulating material with a
relatively low density with increased the hardness characteristics.
Additionally, there is a need for such building materials formed from heat
insulating material that provided lower material costs and provides
building material possessing adhesive and cohesive properties.
Furthermore, there is a need for building materials formed from heat
resistant and heat insulating materials with dielectric properties that
work in conditions of normal, low and high temperatures.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide building
materials formed from heat insulating material with a relatively low
density yet with increased hardness characteristics.
Further, it is an other object of the present invention to provide such
building materials formed from the heat insulating material that provides
lower material costs and provides adhesive and cohesive properties.
It is another object of the present invention to provide such building
materials formed from heat resistance and heat insulating materials with
dielectric properties that work in conditions of normal, low and high
temperatures.
To those ends, a method for making a heat insulated reinforced block of
building material includes providing a mold configured with inner
dimensions equal to a desired configuration of the block of building
material, providing a fluid mixture of heat insulating material formed
from a predetermined composition of ingredients; providing at least one
rigid reinforcement member; placing the at least one reinforcement member
in the mold; introducing the fluid mixture into the mold with the at least
one reinforcement member; allowing the fluid mixture to harden within the
mold and removing the mixture from the mold, resulting in a block of
reinforced heat insulated building material.
It is preferred that the step providing a fluid mixture of heat insulating
material includes providing the fluid mixture of heat insulating material
formed from a composition of the following ingredients and the following
amounts:
Water Glass 32-52% by weight
Sodium Hydroxide 3-4% by weight
Filler 25-36% by weight
Iron Silicon 20-22% by weight
Preferably, the step placing the at least one reinforcement member in the
mold includes placing the reinforcement member in the mold in a
disposition where in at least a portion of the reinforcement member forms
at least a portion of an outer surface of the block of building material
and extends longitudinally along the block.
It is further preferred that the step of providing at least one rigid
reinforcement member includes providing a plurality of reinforcement
members and the step of placing at least one reinforcement member in the
mold includes placing a predetermined number of reinforcement members in
the mold with at least a portion of the predetermined number of
reinforcement members forming at least a portion of an outer surface of
the block. It is preferred that the step of providing a fluid mixture of
heat insulating material includes providing heat insulating material
formed with the ingredients at temperatures in the range between room
temperature and approximately minus 10.degree. C. Preferably, the step of
providing heat insulating material includes providing heat insulating
material as formed through an exothermic reaction that produces a
formulation that hardens without the use of an external energy source. It
is further preferred that the step of providing a fluid mixture of heat
insulating material includes providing a filler formed from firing clay.
Preferably the step of providing a fluid mixture of heat insulating
material includes providing water glass having a SiO.sub.2 /Na.sub.2 ratio
(modulus) that is within the approximate range 2.4 to 3.0 with a density
of approximately 1.41 to 1.47 gm/cm.sup.3. The step of providing a fluid
mixture of heat insulating material also may include providing water glass
formed from sodium silicate.
In another preferred embodiment of the present invention the method
includes the steps of providing a mold configured with inner dimensions
equal to a desired configuration of the block of building material;
providing a plurality of hardened structures of heat insulating material
formed from a predetermined composition of ingredients; providing at least
one rigid reinforcement member; providing a fluid mixture of heat
insulating material formed from the predetermined composition of
ingredients; placing the hardened structures and the at least one
reinforcement member in the mold with the at least one reinforcement
member being disposed between the hardened structures; introducing the
fluid mixture into the mold to surround the hardened structures and the at
least one reinforcement member allowing the fluid material to harden
within the mold and removing the mixture from the mold, resulting in a
block of reinforced heat insulating building material. Preferably, the
steps of providing a plurality of hardened structures of heat insulating
material and providing a fluid mixture of heat insulating material
including providing both the hardened structures and the fluid mixture
formed from a composition of ingredients as described above. It is further
preferred that a plurality of reinforcement members are provided and the
step of placing the hardened structures and the at least one reinforcement
member in the mold includes placing the hardened structures and the
reinforcement members in alternating layers within the mold. It is further
preferred that the step of providing at least one reinforcement member
includes providing the at least one reinforcement member formed as a
generally elongate steel channel. Further, the step of placing at least
one reinforcement member in the mold includes placing the reinforcement
member in the mold in a disposition where in at least a portion of the
reinforcement member forms at least a portion of an outer surface of the
block of building material. It is preferred that the step of placing at
least one reinforcement member in the mold includes placing the
reinforcement member in the mold at a disposition extending longitudinally
along the block. It is also preferred that the step of placing the at
least one reinforcement member in the mold includes placing the
reinforcement member in the mold at a disposition extending width-wise
across the block.
According to another preferred embodiment of the present invention, the
method includes the steps of providing a mold configured with inner
dimensions equal to a desired configuration of the block of building
materials; providing a fluid mixture of heat insulating material formed
from a predetermined composition of ingredients, providing a plurality of
rigid reinforcement members; placing the predetermined number of
reinforcement members in the mold, with the predetermined number
reinforcement members forming at least a portion of first surface of the
blocks; introducing the fluid mixture into the mold with a predetermined
number of reinforcement members; allowing the fluid material to harden
within the mold; and removing the mixture from the mold, resulting in a
block of reinforced heat insulating building material. Preferably the step
of providing a fluid mixture includes providing a fluid mixture of heat
insulating material formed from a composition of ingredients as described
above. Further, the present invention preferably includes the step of
placing a second predetermined number of reinforced members in the mold,
on the fluid mixture prior to hardening thereof at a disposition where in
at least a portion of the second predetermined number of reinforcement
members forms at least a portion of the second outer surface of the block.
The present invention is also directed to a heat insulated, reinforced
block of building material formed from the above-discussed methods. The
block of building material includes a molded polygonal unit having a
predetermined volume and being formed from a hardened fluid mixture of
heat insulating material, the fluid mixture of heat insulating material
being formed from a predetermined composition of ingredients, the unit
having at least one reinforcement member disposed at least partially
internally thereof. Preferably, the fluid mixture of heat insulating
material is formed from a composition of ingredients as described above.
The building material according to the present invention preferably
further includes a plurality of hardened structures of heat insulating
material formed from the predetermined composition of ingredients and
disposed internally within the block with at least one reinforcement
member disposed intermediate at least two of the hardened structures. It
is preferred that the hardened structures are formed from a composition of
ingredients as described above. It is further preferred that the at least
one reinforcement member be formed from steel. Preferably, the at least
one reinforcement member is disposed internally within the unit and
extends width-wise thereof. It is alternately preferred that the unit
include a plurality of reinforcement members extending longitudinally
along the block and at least a portion of the reinforcement members forms
at least a portion of an outer wall of the block.
It is preferred that the heat insulating material be formed through an
exothermic reaction that produces a formulation that hardens without the
use of an external energy source. Further, the filler is preferably formed
of firing clay. It is further preferred that the water glass have an
SiO.sub.2 /Na.sub.2 O ratio (modulus) that is within the approximately
range 2.4 to 3.0 with a density of approximately 1.41 to 1.47 gm/cm.sup.3.
Preferably, the water glass is sodium silicon.
By the above, the present invention provides a method for producing a block
of reinforced building material formed from low density heat insulating
material and building products produced according to the method.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a heat insulated reinforced block of
building material according to one preferred embodiment of the present
invention, broken open to reveal the internal structure thereof;
FIG. 2 is a perspective view of a mold receiving heat insulated material
according to the method of the present invention;
FIG. 3 is a perspective view of a heat insulated reinforced block of
building material according to a second preferred embodiment thereof;
FIG. 4 is a cross sectional view of a mold receiving heat insulated
building material according to a second preferred embodiment of the
present invention; and
FIG. 5 is a cross sectional view of a mold filled with heat insulating
material including reinforcement members according to the method of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings and, more particularly to FIG. 1, the first
preferred embodiment of the present invention is illustrated as a heat
insulated reinforced block of building material broken open to reveal the
inner structure thereof and is illustrated generally at 10. The present
invention includes a method for forming the block as well as at least one
more embodiment thereof. FIG. 1 reveals the block 10 to include a solid
body 12 formed from heat insulating material which will be described in
greater detail hereinafter. Within the body 12, a stack of hardened
structures 14 are provided in alternating layers with elongate steel
channels 16 which provide reinforcement of the block 10. The hardened
structures 14 are formed generally as cubes and are made from the same
heat insulating material as is the body 12 of the block 10. It should be
noted that while cubes are illustrated, the hardened structures 14 maybe
formed as cylinders or any other geometric structure that will provide
positioning for the steel reinforcement member 16 during the molding
process. Once the block is molded, the hardened structures 14 become
substantially integral with the body 12 of the block 10. The reinforcement
members 16 will provide the relatively light block with the ability to
withstand crushing forces and should therefor be disposed in a generally
parallel relationship with the outer surfaces of the block so that the
block may be oriented with the reinforcement members running along the
direction of compression when the blocks are in use.
The second preferred embodiment of the present invention is illustrated in
FIG. 3. There, the block 30 is formed as a generally elongate, relatively
flat wall panel 32 formed from the heat insulating material 18 and
includes four elongate steel channels 34 disposed at four corners thereof
with an outer surface of the steel channels 34 forming a portion of the
outer surface of the wall panel 30. Since the hardened heat insulating
material 18 is relatively brittle and is formed with numerous pores which
provide a rough surface, the smooth outer surface of the steel channels 34
provides the wall panel 30 with a mounting surface which will support
screws, other fasteners or other attachments in general.
Both of the preferred embodiments of the present invention are formed
according to the method of the present invention and require a formulation
of heat insulating material for molding as seen in FIGS. 2 and 4.
According to the formulation for producing a heat insulating material and
the method for making such material, the heat insulating material is made
by mixing an iron/silicon alloy with water glass (sodium silicate, which
is the same as "liquid glass"), thereby providing the water necessary for
the reaction. The reaction follows a path similar to that of the
well-known alkaline corrosion of iron in water to produce hydrated ferric
oxide and hydrogen. The evolution of water resulting from the solvent
evaporation aids in the formation of material with structural integrity.
Additionally, firing clay can act as a binder, which, together with
dehydrated sodium silicate, forms a typical two or three dimensional
matrix of SiO.sub.3 tetrahedra, which likely contributes to the physical
strength of the building products made from the heat insulating material.
The key is in the initial reaction of iron/silicon alloy with water in an
alkaline medium. The reaction initiation is spontaneous and immediate when
the ingredients are mixed and the reaction is completed in a relatively
short time. In addition, the heat insulating material utilized in the
present invention is stable when exposed to high temperatures and is based
on inorganic materials. Further, the heat insulating material is made from
a formulation that uses sodium silicate and produces a foam without the
use of either an anionic surfactant, chromium or aluminum. Finally, the
heat insulating material does not require the use of high temperature
firing or pressure molding.
The formulation involves an exothermic reaction which depends on sodium
silicate or liquid glass, sodium hydroxide, iron silicon and a filler,
such as the aforesaid firing clay. More specifically, iron silicon reacts
in an exothermic reaction in an alkaline medium resulting in a rapid
release of energy in the form of heat. As a result of the exothermic
reaction, the mixed formulation self-heats to temperatures near
100.degree. C. The formulation becomes porous as a result of the formation
of water vapor and hydrogen, and hardens as a result of water loss. Pore
formation results in an increase of many times the volume and lowers the
density of the resulting heat insulating material and, consequently, the
weight of building materials formed from the material. The loss of water,
in addition to contributing to pore formation, also leads to an increase
in the dielectric qualities of the material. Additionally, the reaction of
the iron component in iron silicon contributes to the heat resistance of
the resulting heat insulating material.
The presence of sodium hydroxide is necessary for the reaction of the
formulation that results in the heat insulating material and makes it
possible for the reaction to occur at normal room temperature or at
temperatures down to -10.degree. C. Sodium hydroxide contributes to the
speed with which the reaction occurs, thus insuring an adequate
temperature rise and the evolution of water which results in pore
formation. The increased temperature also facilitates water loss, thus
contributing to the hardening of the heat insulating material.
The firing clay in the formulation provides for the necessary viscosity of
the initial mixture, and contributes to the heat resistance of the heat
insulating material. Other materials, such as kaolin or other finely
dispersed powders, which perform analogous functions in providing
viscosity and heat resistance, may be used instead of firing clay.
The ratio of SiO.sub.2 to Na.sub.2 O (modulus) for the sodium silicate or
liquid glass is in the approximate range of 2.4 to 3.0, given the density
of 1.41 to 1.47 g/cm.sup.3. The values of the dispersion of the iron
silicon are determined by the specific area of 0.004 to 0.005 cm.sup.2 /g,
which allows for varying the viscosity of the formulation and its
reactivity.
In general, the formulation for producing the heat insulating material
having the qualities described above is prepared using the following basic
steps:
(a) Granules of sodium hydroxide are added to the liquid glass and the
solution is agitated to ensure complete dissolution. The iron silicon and
the firing clay are added.
(b) The mixture is again agitated until a homogeneous plastic consistency
is achieved and is then poured into a form or mold, as will be described
in greater detail hereinafter.
(c) The resulting heat insulating material expands and hardens under normal
conditions within 1 to 1.5 hours, substantially filling up the volume of
the form or mold.
Further, in the process of hardening, hydrogen is produced, and during the
final stage of hardening, water vapor is evolved as the product
temperature rises to near 100.degree. C. as a result of the reaction
exothermicity.
In Table 1 shown below, examples of different fillers/binders are
identified for use in the proposed formulation of the present invention in
which part of the firing clay is replaced with the proposed filler. In
this manner, the proposed formulation may be used with various fillers as
a means for producing materials having the desired physical-mechanical
properties.
TABLE 1
Compound - Binder Component Mass %
Liquid Glass -52
Sodium Hydroxide 4
Firing Clay 16
Iron Silicon 28
Filler/Binder = 3/1
Parameter Sand/Binder Ceramic/Binder
Density - Kg/m.sup.3 1750 760
Limit of Hardness under Compression - 37.4 5.32
MGa
Heat Transfer Coefficient - Wt/m. .degree. C. 0.85 0.54
Time of Hardening - Min. 120 120
Working Temperature Range - .degree. C. 1400 1100
The possible reactions in the formulation of the present invention for the
heat insulating material are:
1. Fe+2H.sub.2 O.fwdarw.Fe(OH).sub.2 +H.sub.2 (alkaline medium)
2. 2Fe(OH).sub.2 +O.sub.2 (air)+xH.sub.2 O.fwdarw.Fe.sub.2
O.sub.3.multidot.(x+2)H.sub.2 O
Reactions 1 and 2 represent a normal oxidation process which will be more
rapid in the presence of finely divided iron. The reaction is exothermic.
Mixing FeSi with a few drops of 0.5M NaOH produces rapid warming,
indicating that reaction 1 is indeed proceeding. Since the entire process
is carried out "in the open", air is surely present to supply oxygen for
reaction 2. The expected water of hydration will be lost as the
temperature of the mixture increases.
3. 2FeSi+3O.sub.2.fwdarw.2FeSiO.sub.3
Reaction 3 is one of the possible reactions in slag formation and may
indeed occur here. Normally one would expect this silicate formation to
occur at higher temperatures such as might be found in steel making ovens.
The extent to which this reaction occurs will reduce the observed weight
loss in the thermo-gravimetric analysis by reducing the extent of
involvement of reaction 1 and by adding weight through oxygen
incorporation. It is unlikely that reaction 3 occurs to any significant
extent given the weight loss result reported below.
4. Si+H.sub.2 O+2NaOH.fwdarw.Na.sub.2 SiO.sub.3 +2H.sub.2
Reaction 4 is also exothermic and releases hydrogen gas.
Isothermal (28.degree. C.) thermo-gravimetric analysis of the entire system
as supplied, resulted in a weight loss of 13.9%. The sodium silicate used
is a 42.degree. Beaume product containing 29.6% SiO.sub.2, and 9.20%
Na.sub.2 O and therefore 61.2% water. On total material composition, this
amounts to 23.2% water. Taking the composition of FeSi into account
(approximately 25% Fe and 75% Si), the weight loss due to hydrogen
evolution (reaction 1) is expected to be 0.27%. The weight gain due to
oxidation (reactions 1 plus 2) amounts to 3.7%. Thus, the theoretical
weight loss is expected to be 19.8%. In a second thermo-gravimetric
analysis performed on the reaction product and carried out in stepped
temperature mode, an additional weight loss of 4.9% on total reaction
charge was measured giving a total weight loss of 18.8%, which compares
reasonably with the theoretical.
In summary, the formulation for producing a heat insulating material has a
self-starting exothermic chemical reaction which hardens the heat
insulating material. The chemical reaction can occur in the temperature
range between normal room temperatures and 10.degree. C., and does not
require an external heat source. The percentages of the components of the
formulation are:
Water Glass 32-52% by weight
Sodium Hydroxide 3-4% by weight
Firing Clay 25-36% by weight
Iron Silicon 20-22% by weight
Returning now to FIG. 2, the reinforced block of building material
according to one preferred embodiment of the present invention is formed
according to the method of the present invention using the formulation
previously described. First, the internal structure is formed which may be
seen in FIGS. 1 and 2. As also previously described, a preformed mold (not
shown) is used to form a plurality of cubes of the heat insulating
material. The cubes are allowed to harden and are then arranged within the
mold. A first cube is placed in the mold and a steel channel is placed on
top of the cube. The cubes in the channel are placed within the mold in an
alternating manner to arrive at the stack illustrated in FIGS. 1 and 2.
The mold 20 is formed from wood or other material to define a mold interior
22 for receiving the stack of hardened structures 14 and steel channel 16.
The mold is preferably rectangular but is not limited to a rectangular
configuration. Nevertheless, the regular shape offered by a rectangular
mold lends itself well to producing blocks of building material. The heat
insulating material 28 if formed according to the formulation described
above and is poured from a vessel 26 or otherwise introduced into the
interior 22 of the mold 20 to completely fill the mold. As seen in FIG. 5,
a top portion 24 is placed on the upper surface of the insulating material
28 to define a six-sided structure once the mold is removed. It should be
noted that while the insulating material 28 is shown being poured from a
bucket 26, this technique is generally performed at a building site and
the mass production of blocks according to the present invention will
likely progress with the heat insulating material 28 flowing from a piping
system or other delivery system. Therefore, it should not be presumed
under any conditions that the heat insulating material 28 must be poured
into the mold 20. In any event, the heat insulating material 28 is allowed
to harden and the mold is broken away from the structure formed therein
which provides the block 10 as illustrated in FIG. 1.
According to another preferred embodiment of the present invention, and
with reference to FIG. 4, two steel channels 34 are placed in the bottom
of the mold and the heat insulating material 28 is introduced into the
interior 22 of the mold as previously described. With reference to FIG. 5,
once the mold 20 has been filled with heat insulating material 28, two
more steel channels 34 are disposed at upper surface of the heat
insulating material 28. As seen in FIG. 5, a top 24 is placed on the steel
channels 34 and the flowable heat insulating material 28 is allowed to
harden into a hardened heat insulating material 18 as described in the
discussion of the formulation. It will be apparent that those skilled in
the art that the amount of heat insulating material introduced into the
mold 28 must be regulated as the material expands when it cools. Trial and
error or sophisticated density/volume calculations can provide the
necessary amount of flowable material that will fill up the mold. Further,
it is contemplated if the blocks are produced in great numbers, a computer
may be employed to feed heat insulating material into the mold 20 in
metered amounts sufficient to provide the necessary structure while not
overfilling the mold. Once the heat insulating material 18 has hardened,
the mold may be removed from around the block 10 and the block 10 then
used for building material.
Blocks according to the present invention have many uses and can form mold
structures to provide light, heat insulated and heat resistant walls for a
building. Further, interior wall panels may be placed over the outer steel
channels of the blocks illustrated in FIG. 3. Therefore, the present
invention provides a lightweight, strong material for construction
purposes.
It will therefore be readily understood by those persons skilled in the art
that the present invention is susceptible of a broad utility and
application. Many embodiments and adaptations of the present invention
other than those herein described, as well as many variations,
modifications and equivalent arrangements, will be apparent from or
reasonably suggested by the present invention and the foregoing
description thereof, without departing from the substance or scope of the
present invention. Accordingly, while the present invention has been
described herein in detail in relation to its preferred embodiment, it is
to be understood that this disclosure is only illustrative and exemplary
of the present invention and is made merely for purposes of providing a
full and enabling disclosure of the invention. The foregoing disclosure is
not intended or to be construed to limit the present invention or
otherwise to exclude any such other embodiments, adaptations, variations,
modifications and equivalent arrangements, the present invention being
limited only by the claims appended hereto and the equivalents thereof.
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